Départment of Information Technology
MIET
ASSIGNMENT SHEET 1
Q1. Discuss the advantages of database system over file processing system.
Q2. Explain the three schema architecture of DBMS. Give suitable example to represent the three levels.
Q3. What do you understand by the term data abstraction? State the significance of mapping between the
various levels of three level architecture of DBMS.
Q4. What are the different types of database users who interact with database system? List the responsibilities
of the DBA.
Q5. Draw the overall structure of DBMS and state the functionality of the different components of the structure.
Q6. Discuss the candidate key, primary key, super key, alternate key, and secondary key.
Q7. Explain specialization, generalization and aggregation. Give suitable example in support of your answer.
Q8. Draw an E-R diagram of the book club. The book club has members. The book club sales books to its
members. The member places orders for books, which the book club fulfills. Each order contains one or more
than one books. The books are written by author(s). The publisher publishes the books and the author can write
more than one book and a book can have more than one author. A book is published by publisher, but a
publisher publishes many books. A member can place more than one order. He also can choose not to place an
order. The book club sales many books.
Q9. What is the purpose of the E-R diagram? Construct an E-R diagram for a university system which should
include information about students, departments, professors, courses, which students are enrolled in which
course, which professors are teaching which courses, student grades, which course a department offers. Make
suitable assumptions wherever required.
Q10. Construct an E-R diagram for a hospital with a set of patients and a set of medical doctors. Associate with
each patient a log of the various tests and examinations conducted.
ASSIGNMENT SHEET 2
[RCS-501 Database Management System]
Départment of Information Technology
MIET
Q1. Consider the following relation schemes:
Project (Project#, Project_name, chief_architect)
Employee (Emp#, Empname)
Assigned_To (Project#, Emp#)
Give expression in Tuple calculus and Domain calculus for each of the queries below:
(i) Get the employee numbers of employees who work on all projects.
(ii) Get the employee numbers of employees who do not work on the COMP123
project.
Q2. Define the five basic operators of relational algebra with an example each.
Q3. Explain entity integrity and referential integrity rules in relational model. Show how
these are realized in SQL.
Q4. Consider the following relations:
S (S#, SNAME, STATUS, CITY)
SP (S#, P#, QTY)
P (P#, PNAME, COLOR, WEIGHT, CITY)
Give an expression in SQL for each of queries below:
(i) Get supplier names for supplier who supply at least one red part
(ii) Get supplier names for supplier who do not supply part P2.
Q5. Define a view and a trigger. Construct a view for the above relations which has the information about
suppliers and the parts they supply. The view contains the S#,SNAME, P# , PNAME renamed as SNO, NAME,
PNO, PNAME.
Q6. Differentiate between the following: (i) Theta Join. (ii) Equi Join. (iii) Natural Join
(iv) Outer Join.
Q7. Explain the integrity constraints: Not Null, Unique, Primary Key with an example each. Is the combination
‘Not Null, Primary Key’ a valid combination. Justify.
Q8. Explain the followings :
(i) Nested Queries.
(ii) Cursors in SQL.
Q9. Consider the following relational schemas:
EMPLOYEE (EMPLOYEE_NAME, STREET, CITY)
WORKS (EMPLOYEE_NAME, COMPANYNAME, SALARY)
COMPANY (COMPANY_NAME, CITY)
Specify the table definitions in SQL.
Q.10 Give an expression in SQL for each of queries below:
(i) Find the names of all employees who work for first Bank Corporation .(ii) Find the names and company
names of all employees sorted in ascending order ofcompany name and descending order of employee names of
that company.(iii) Change the city of First Bank Corporation to ‘New Delhi’
[RCS-501 Database Management System]
Départment of Information Technology
MIET
ASSIGNMENT SHEET 3
Q1. Suppose you are given a relation R = (A,B,C,D,E) with the following functional
dependencies: {CE  D,D B,C A}.
a. Find all candidate keys.
b. Identify the best normal form that R satisfies (1NF, 2NF, 3NF, or BCNF).
c. If the relation is not in BCNF, decompose it until it becomes BCNF. At each step, identify a
new relation, decompose and re-compute the keys and the normal forms they satisfy.
Q2. You are given the following set of functional dependencies for a relation R(A,B,C,D,E,F),
F = {AB  C,DC AE,E F}.
a. What are the keys of this relation?
b. Is this relation in BCNF? If not, explain why by showing one violation.
c. Is the decomposition (A,B,C,D) (B,C,D,E,F) a dependency preserving decomposition? If not,
explain briefly.
Q3. You are given the below set of functional dependencies for a relation R(A,B,C,D,E,F,G),
F = {AD BF,CD EGC, BD F,E D, F C,D F}.
a. Find the minimal cover for the above set of functional dependencies using the algorithm described
in class. Give sufficient detail to show your reasoning, but be succinct. You do not have to list all
the cases you test/consider for the algorithm. Show all steps where you make changes to the above
set in detail.
b. Using the functional dependencies that you computed in step a, find the keys for this relation.
Is it in BCNF? Explain your reasoning.
c. Suppose we decompose the above relation into the following two relations:
R1(A,B,C,D,E) R2(A,D,F,G) Use the functional dependencies in the minimal cover. For each relation, write
down the functional dependencies that fall within that relation (you can decompose a dependency of the form
AD BF into two i.e. ADB and AD F when computing this).
Q4. Given relation R(W, X, Y, Z) and set of functional dependencies F = {X W,WZ XY, Y  WXZ}.
Compute the minimal cover for F.
Q5. Given R(A,B,C,D, E) with the set of FDs, F(ABCD,A E,CD). Is the
decomposition of R into R1(A,B,C), R2 (B,C,D) and R 3(C,D,E)lossless? Prove.
Q6. What do you understand by transitive dependencies? Explain with an example any two problems that can
arise in the database if transitive dependencies are present in the
database.
Q7. List the Armstrong’s axioms for functional dependencies. What do you understand by soundness and
completeness of these axioms?
Q8. Consider the decomposition of relation scheme, shipping = (Ship, Capacity, Date,
Cargo, Value) with the set of functional dependencies, F = {Ship Capacity
Ship, Date Cargo, Cargo, Capacity Value} into R1={Ship, Capacity} with F1 =
{Ship Capacity} and R2 ={Ship, Date, Cargo, Value} with F2={Ship, Date Cargo,
Value}. Is this decomposition in BCNF? Is this decomposition lossless and dependency preserving? Justify your
answers.
Q9. Define functional and multi-valued dependencies.
Q10. What are the three data anomalies that are likely to occur as a result of data redundancy? Can data
redundancy be completely eliminated in database approach? Why or why not?
[RCS-501 Database Management System]
Départment of Information Technology
MIET
ASSIGNMENT SHEET 4
Q1. List the ACID properties. Explain the usefulness of each.
Q2. During its execution, a transaction passes through several states, until it finally commits or aborts. List all
possible sequences of states through which a transaction may pass. Explain why each state transition may
occur.
Q3. Justify the following statement: Concurrent execution of transactions is more important when data must be
fetched from (slow) disk or when transactions are long, and is less important when data is in memory and
transactions are very short.
Q4. Consider the following two transactions:
T1: read(A); read(B); if A = 0 then B := B + 1; write(B).
T2: read(B); read(A); if B = 0 then A := A + 1; write(A).
Let the consistency requirement be A = 0 B = 0, with A = B = 0 the initial values. a. Show that every serial
execution involving these two transactions preserves the consistency of the database. b. Show a concurrent
execution of T1 and T2 that produces a nonserializable schedule. c. Is there a concurrent execution of T1 and
T2 that produces a serializable schedule?
Q5. What is a cascadeless schedule? Why is cascadelessness of schedules desirable? Are there any
circumstances under which it would be desirable to allow noncascadeless schedules? Explain your answer.
Q6. Compare the shadow-paging recovery scheme with the log-based recovery schemes in terms of ease of
implementation and overhead cost.
Q7. When the system recovers from a crash (see Section 17.6.4), it constructs an undo-list and a redo-list.
Explain why log records for transactions on the undolist must be processed in reverse order, while those log
records for transactions on the redo-list are processed in a forward direction.
Q8. Assume that immediate modification is used in a system. Show, by an example, how an inconsistent
database state could result if log records for a transaction are not output to stable storage prior to data updated
by the transaction being written to disk
Q9. Compare the deferred- and immediate-modification versions of the log-based recovery scheme in terms of
ease of implementation and overhead cost.
Q10. Explain the purpose of the checkpoint mechanism. How often should checkpoints be performed? How
does the frequency of checkpoints affect
[RCS-501 Database Management System]
Départment of Information Technology
MIET
• System performance when no failure occurs
• The time it takes to recover from a system crash
• The time it takes to recover from a disk crash
ASSIGNMENT SHEET 5
Q1. Consider the following two transactions: T31: read(A); read(B); if A = 0 then B := B + 1; write(B). T32:
read(B); read(A); if B = 0 then A := A + 1; write(A).
Add lock and unlock instructions to transactions T31 and T32, so that they observe the two-phase locking
protocol. Can the execution of these transactions result in a deadlock?
Q2. Consider the validation-based concurrency-control scheme of Section 16.3. Show that by choosing
Validation(Ti), rather than Start(Ti), as the timestamp of transaction Ti, we can expect better response time
provided that conflict rates among transactions are indeed low.
Q3. For each of the following protocols, describe aspects of practical applications that would lead you to
suggest using the protocol, and aspects that would suggest not using the protocol: • Two-phase locking • Twophase locking with multiple-granularity locking • The tree protocol • Timestamp ordering • Validation •
Multiversion timestamp ordering • Multiversion two-phase locking.
Q4. Explain the phantom phenomenon. Why may this phenomenon lead to an incorrect concurrent execution
despite the use of the two-phase locking protocol?
Q5. Show that there are schedules that are possible under the two-phase locking protocol, but are not possible
under the timestamp protocol, and vice versa.
Q6. Discuss the relative advantages of centralized and distributed databases.
Q7. Give an example where the read one, write all available approach leads to an erroneous state.
Q8. Stable storage cannot be implemented. a. Explain why it cannot be. b. Explain how database systems deal
with this problem.
Q9. Explain the difference between the three storage types—volatile, nonvolatile, and stable—in terms of I/O
cost.
Q10. Use of multiple-granularity locking may require more or fewer locks than an equivalent system with a
single lock granularity. Provide examples of both situations, and compare the relative amount of concurrency
allowed.
[RCS-501 Database Management System]
Départment of Information Technology
[RCS-501 Database Management System]
MIET